The California Fairs.Messrs. Editors :—While waiting to keep an engagement in this Fair building of the Mechanics' Institute of San Francisco, I am reminded that your readers might be pleased to see even a hasty sketch of the two California Fairs--the State Fair at Sacramento recently closed, and this one at San Francisco, recently opened. Of the State Fair at Sacramento I cannot say too little ; while of this one I can scarce say enough, in the little space at your disposal for .such a purpose. To say that the State Fair, so much and so loudly heralded, was a disgrace to California, and would have been unworthy as an exhibition of the industry and productions of any fourth-rate county within her borders, is to speak a simple truth. The one thing which seems to have en grossed the faculties of the managers, was the half-mile race course. '{'he entire machinery departm ent consisted of a boiler, engine, and shafting—all the requisites for machines in motion, without a single machine of any kind to be thus exhibited ; a part of the space set apart for this purpose was used for the display of a slim collection of agricultural implements. Pleasanter far is the duty of calling attention to this Fair of the Mechanics' Institute, held in a building some 250 by 150 feet, provided with double galleries on each side of the nave (which is not far Jrom 75 ;feet wide and 50 feet high) constructed for t he purpose, and well filled in every part with articles of use and novelty. The central feature of the main exhibition room is an oval shaped fountain, aronnd which, and freshened by the ceaseless play of the waters, the most tempting fruits are di splayed —fruits of all seasons and of almost every clime. Beans and blackberries, apples and apricots, grapes and lemons, melons and oranges, pears and pomegranates, peaches and pumpkins, plums and potatoes, peppers and quinces, strawberries and squashes. Turnips and vegetables, of every kind, are exhibited in great profusion, while pilfering fingers are restrained by the intervention of coarse wire nettings. Flowers and plants, too, of number and variety uncounted, are assigned places in the immediate vicinity ; and behind them again are stands, where new cider is made, which, with California Vichy water, slakes thirst for the thirsty. The general effect of the decorations of the room is excellent . Indeed the exhibition of taste in the arrangement of draperies and in the classification of articles is well worthy the attention of our American: Institute managers. Without attempting to particularize, I will content myself with a partial enumeration of articles which attract my .attention as especially novel or useful. Not the least of these is the Patent Agency—where a variety of quaint models appear, and behind them two specimens of printing presses, one a power and the other a hand press. On the latter is being printed a facsimile of Ben Franklin's first newspaper, copies of which are in very good dem and at a duns each. A suspension bridge connects the galleries near the fountain, and enlightens the otherwise ignorant as to the modes of making and using wire cables for such purposes. The bridge is the joy ot all juvenile and many senile visitors. Did you never think of the advantages of windows without weights ? Here is Sullelt's ball window catch which holds either upper or lower sash at the precise point desired—a more simple and effective appliance for the purpose than I have heretofore seen. Dreamed you never of an endless band saw for scroll as well as heavy work ? Many a time have I, and my dream here has substantial shape in the contrivance of Otis Jackson. The wheels upon which the saw moves are about five feet diameter, made of iron, tired with leather ; and the ends of the saw are skillfully brazed together, forming, Substantially, an endless belt. Have you broken your b:tck at your father's wood pile ? Then you toould look with pleasure on Noel's application of crank power to a common buck-saw, worked in connection with a common buck for the wood. And if the pump were as absolute a necessity in New York as it is in California, your eyes would sparkle at sight of At- wood&Bodwell's self-regulating wind-mill for operating it, and also at that of the Gerrish submerged force pump as a substitute for the usual style of the article. Had you plowin g to do, and Califo rnia soils in p lace of the stony hardnesses of New England, you would debate less upon the instrument itself than upon the ease of the scat. The several gang plows in use here do their work well, ami all of them provide a comfortable seat for the driver, while the work .goes on, Nearly a dozen d ifferent specimens of gang plows, the work of as many different makers, are here on exhibition. They consist of two plows managed in connection with a two-wheeled vehicle on which the driver rides. If the construction of water and sewer pipes required your consideration,' you would doubtless respect the asphaltolin pipes, and wonder why the same material might not be applied to tunnels of large caliber. A blower on Root's plan, built at the Globe Works,.stock October 23, 1869.] Jtieutifit J^mafam 263 ton , would not seem wonderlul, because you will find a larger instrument in your city. Enough, however, of machinery, and almost enough of the Fair. Let us enter only, before we leave, this large rqqm built and lmed with the different kinds of wood which grow in California. The wood riches of all the earth are seemingly gathered here, so many are the kinds and so well polished the specimens. Strahle&Hughes, who exhibit, call it the “ Laurel Palace,” and a palace it certainly is—worthy the Fair and worthy the State.B. San Francisco, Sept. 27, 1869. Oa the Assimilation of Inorganic Substances in the Aniinal Economy. Messrs. Editors :—The idea that inorganic substances are not assimilated in the animal organism, advanced by a correspondent, pages 166 and 280, current volume, is a favorite theory of the so-called vegetable or Indian doctors, to which class his authority, Dr. Bellows, appears to belong. The theory in question is founded on the obscure notion that some mysterious change takes place when an inorganic compound is absorbed in a vegetable, that it is vitalized, and that only vitalized com pounds can be appropriated by living animals. Unfortunately this theory is not borne out by the facts; the very contrary is true. It might, with some slight chance of snc cess have been defended many years ago, when the sciences of synthetic organic chemistry and biology were yet unborn ; but since we have learned to compose many so-called organic compounds, for instance, alcohol, gum, sugar, etc., and even urea and several other animal substances, out of their constituent elements—without the aid of living organisms—and that these thus artificially manufactured substances are perfectly identical, to all intents and purposes, to those derived from the usual organic channels, and act on the animal system in the same manner, the doctrine of the so-called “ vitalism” is exploded. Vie know now, also, that there is no difference whatever between phosphates, sulphates chlorides, etc., if made by art or derived from vegetable sources, so th at, for instance, the phosphate of lime or soda, naturally found in the bran of flour is not in the least different from ,'ny other compound of that name, from whatever source it be derived, provided it be pure. In regard to the main point, the absorption and assimilation of inorganic matter, in the animal body ; thi!; is a so well established fact as to make the contrary assertion almost unworthy of contradiction. Water is certainly an inorganic compound, and this is so largely assimilated that the great portion of the bodies of all animals consists of water; the salts contained in the divers mineral waters, are so thoroughly assimilated as to cause changes in the constitution of the individuals using them, even the external applications in the shape of sulphur and other baths, have similar effects ; and lead, mercury, arsenic, etc., either externally or internally, are so thoroughly assimilated as to cause painters' colic, the mirror-makers' paralysis, and the finding of arsenic in the very boiies of the subject. In such cases the antidotes must also be assimilated in order to find the poisons and perfect a cure. It may be asserted that these cases must not be called assimilation, and are oniy an absorption, because such substances do not belong in the living organism ; by the following facts, however, I will prove that if substances belonging to the organism are absorbed in the same manner, they finally perform all the functions of assimilated. ingredients. The cause of chlorosis is that the digestive apparatus is unable to absorb the small amount of iron present in many kinds of food. Now experience has taught, in general, that if certain necessary substances are not absorbed, all that we have to do is to present these very substances in large quantities, and that finally the system will be comp ell oil to absorb them. So in chlorosis, iron is administered with the food, either as a metallic powder, an oxide, or as a chalybeate mineral water ; if inactive, the dose is simply increased, and finally in so,ne cases the disease is only overcojne, by giving extraordinary large doses, which compel the system more forcibly to absorption. If once absorbed the difficulty is overcome, assimilation follows at once. Recent investigations have shown that a small quantity of manganese is always present in the blood with tho iron, and as the iron administered is always chemically pare, it was suggested that some cases of failure in the iron treatment might be due to the absence of the necessary manganese:. The idea was at once acted upon, ami now, in case >of non-succe88 of the iron treatment, all physicians who are posted up ill regard to the progress of their art, add a small quantity of manganese or a suitable manganese compound to the iron, and always with perfect success. The iron and manganese pills, or quinine and manganese pills, have, in fact, become a standard prescription. If any one still doubts assimilation of inorganic substances by the blood, let him try to take phosphate of iron daily. Many individuals will soon find that their blood becomes so rich under this treatment that it shows itself in pimples over the face and elsewhere. Many pot"-8h compounds have the same effect. The above will suffice, I believe, to settle the point in question, and I will only add that the assimilation of inorganic compounds seems highly probable, if not proved, by the following facts : The rapid cure of sore gums by internal use of chlorate of potash ; the prevention of morbid profuse perspiration by the internal use of mineral acids ; the cure of epilepsy by sulphate of zinc; the blue coloring of the skin by internal use of nitrate of silver ; the sedative effect of bromide of potassium ; the resultant brittleness of the bones by the prolonged use of iodides ; the nourishing effect of lime water, if added to milk or certain other kinds of food. P. II. Vander Weyde, M. D. 'J'yndall's Theory of Cornets. Messrs. Editors :—In your notice of the ingenious theory of Dr. Tyndall (p. 219), in relation to comets, I find a corroboration of a belief of my own that “ all space is filled with imponderable matter except the small part occupied by the planets—which are themselves pervaded by the same—and that this ungravitating matter is the medium for the action of the imponderable agents, electricity, magnetism, etc., which agents are the manifestation of different elements of that matter." The nucleus of a comet is no doubt ponderable, as it observes the laws of gravitation, but is so rare and transparent that it obstructs only the calorific rays, while the actinic, passing through, precipitate the imponderable matter of space, rendering it visible, the same as they precipitate invisible vapor of water or other matter, this being again dissipated as soon as tlie shadow is removed. If the nucleus were an opaque body the shadow would be a cone, unlike a comet's tail, but being transparent the rays passing through are more or less refracted and reflected; causing thisto assume various shapes, ac- coi'ding to the nature of the interruption or the varying direction of the deflection. May not the “ luminous envelopes” which surround the nucleus, and which you say are not accounted for by his theory, be, on the other hand, a corroboration of it; if it is admitted that the sun's actinic rays may be reflected from the surface of the nucleus, or from surfaces within it, into the spaces immediately around it, with even greater power than have those which pass through with but little refraction ? This theory, if correct, makes of the sun almost a creator, realizing the dreams of the magi. As the” vortical” theory of Laplace and Herschel, if true, demonstrates that there was a time when creation commenced, and therefore a power which instituted at that time a new sun, so I do not despair of our yet finding out the way in which it was done. Because we know that gravitation was infused into some matter, it does not follow that all matter is subject to it.Charles Boynton. . How to Kill the Fleas and. the Dog. Messes. Editors :—Your correspondent, G. W. B., on page 230 of the present volume, says that “ a mixture of carbolic acid with water—one fourth acid, three fourths water—put on a dog will kill fleas at once.” There is a somewhat important omission here—it will kill the dog also. Your correspondent undoubtedly means one fourth, of the saturated aqueous solution of carbolic acid, three fourths water. Carbolic acid is a crystalline substance (chemically an alcohol rather than an acid),. which is soluble only to the extent of 5 per cent in water. A solution for the purpose of killing parasites on animals should contain little more than 1 per cent of carbolic acid to 99 per cent of water. There is a very dangerous concentrated fluid carbolic acid in the market, consisting often of 90 per cent of the pure add, dissolved in some of the hydrocarbons associated with it in the process of manufacture. I have purchased this of a druggist of the highest reputation in the city of New York under the name of “ solution of carbolic acid,” and have suffered accidentally in consequence from its cauterizing effects. I have been cognizant also of several serious accidents from confounding this concentrated fluid with the satU1'aterl aqueous solution of carbolic acid, which is perfectly safe and strong enough for all applications, except surgical, to the living subject, It is important that some nomenclature should be agreed upon, and rigidly adhered to, to distinguish these preparations. Otherwise, in the extended use of carbolic acid, fatal accidents will be liable to occur. WM. Ji'. CnAN2,iNC!, M. D. Providence, R. I. Scmsth's Improvement in Glass Window Mghts. Messrs. ^Editors :—1 call your attention to an error in your notice of Demuth's Glass Window-lights, published in your edition of October 16. You state that the illuminatin g power of the light transmitted through the rods is not materially impaired, whereas it is not only not impaired but on the contrary materially increased, or at least concentrated to such a degree th at the back part of an apartment will become nea.rly as light as the front containing the lights. The refracting power of the rods, which like so many lenses collect the radiating rays into a parallel beam, produces this effect, which can never be obtained by flat panes, and which, with rods of different tints, is exceedingly beautiful. By publishing the above correction you will oblige New York city.Victor E. Maugeb, Fresh Water at the Seaside. Messrs. Editors :—Through the constantly shifting sands of Cape Cod, sixteen to twenty feet from high water and not more than three feet above it, is sunk an iron tube to a depth of fifteen feet, at which point is found fresh water of the sweetest quality and in inexhaustible quantity, which rises and falls in the tube regularly with the tide of its near neighbor the Atlantic ocean. Yet though more than one hundred barrels have been pumped from it at one time, not the slightest trace of saline matter has been found to mar the freshness of its taste. Of such fine quality is it that vessels supply themselves for a sea voyage from this well. I think the above facts may prove themselves a curiosity to others as well as myself, and that you will be able to give an explanation of the phenomenon through your columns. North Brookfield, Mass.Joiin Q. Adams. Glass Manufacture in the United States. Messrs. Editors :—Some singular statements get into newspapers sometimes. Here is one copied from the Boston Commercial Bulletin of Sept. 11, that for accuracy is not much to be depended upon. Under “ Pittsburgh Items” it says, “ In June last, Redid,&Co. began the manufacture of extra annealed flint glass lamp chimneys—they are the only manu- factuiers who anneal their chimneys—which process renders them strong and clear." It is most assuredly the first time that the wonderful revelation has been made that glass is rendered clear by annealing, and thewho have made researches upon thin subject have been sadly in the dark if we are to believe Messrs. Redick&Co. Yet Reaumur, Dartigues, Dumas, Bon- temps, and others, all agree that glass slowly cooled (annealed) may be devitrified, that is to say, that in cooling glass slowly, the elements arrange themselves in such a manner as to form a certain refined crystalline silicate, which separates from the remaining mass and produces thereby a milky and rough grained glass. If the object of publishing such a statement is to sell the wares, it is a poor kind of a puff; and instead of recommending the goods it advertises the ignorance of the manufacturers. While on this subject of glass, let me say a word in regard to the comparative degree of efficiency between European and the American manufactories. It is universally conceded, that although we have vastly progressed in this country, especially in pressed glass ware, we are still sadly behind hand in many branches. It is true we are making a very fair article of plain window glass, but have we yet made any colored window glass ? Can we compete with the French, the English, for fine cut glass '/ Can we imitate or excel the Bohemian in fancy colored glass 'I Can we rival with the French, English, and Belgian manufacturers in making plate glass ? Do we generally produce as fine an article of glass as the French and Bohemians do ? Have we ever applied etching to glass as it is now so extensively done in France, or have we yet made any trials in applying photography to ornamenting glass ? With the exception of one or two cases, have we used the Siemens furnaces with as much success as they have in Europe? Can we imitate the artistic chefs d'aiuvre 01 production that are to be seen in Europe in the chandelier and fountain line 'I Do we gild and paint glass like the French and Bohemians ? Can we generally produce those marvelous articles blown by the l<'rench, so thin, so brilliant, and “o regular in workmanship ? To the above and to many other questions I fear' we must give a negative answer. The aim of most of our glsss manu- fai'turers has been to improve simply in pressed wares ; a very worthy object it is true, yet it is well known that pressed glass can never attain the perfection of blown and cut wares. An inexperienced person will soon be able “to distinguish one from the other, and there is a limit beyond which improvements in pressed wares can not go. Improvements in presses have been made to render them easy to work and to adapt them to different sizes of molds. Molds have been made with combinations to mold all sorts of shapes. Some have been quite successful, but for all that, all pressed glass bears its stamp and. can Dot be compared to blown and cut glass. Is is not time then for some of our glass manufacturer to devote their time and intelligence to other purposes ? With the exception of one or two Eastern manufacturers, we have but little or no colored glass made in this country. Where is the fault ? It cannot be the cost for we have plenty of materials and at reasonable prices. I fear it is not this but the want of the skillful labor they have in Europe. It is a crying shame that we should send to Europe for all the plate glass we use, and we use a large quantity of it, while we have everything in profusion in this conntry to make glass. Attempts have been made in this country to make plate glass but so far have been unsuccessful. Another attempt is now being made at New Albany, Indiana, according to a communication printed lately in the Scientific American. Let us hope that this, like the others, will not be a failure, but I think I can say, almost positively, that the non-success of these enterprises is not due to disadvantages in materials, but is attributable to an over-confidence and self-reliability in the knowledge of those who undertook it without having skilled and experienced hands to help them. Mr. Lockwoode, in the communication above referred to, says, that “ there is no such word as fail in the dictionary” of the gentleman “at New Albany. Let us hope that he may not be called to print it. Washington, D. C.C. Colne. Testing Boilers. Messes. Editors :—Sometime since a correspondent suggested a boiler test, to be tried at the present Fail' of the American lust it ate. It consisted in connecting the boilers to be tested to a 40-horse power engine, arranged to drive an immersed screw propeller ; the boiler which would produce the greatest number of revolutions of the propeller with a given a]1;1ount of coal, to be adjudged tho “champion boiler." There would, doubtless, be some fallacies involved in a test of this kind. The power required to put a propeller in motion is dependent, to a great extent, upon the velocity with which it revolves, varying ne;;rly as the square of the velocity. For example, it would require one hundred times the power, per revolution, to communicate one hundred revolutions per minute to the propeller, that it would take to communicate ten. Consequently, if the proposed test were put in practice, the “ champion boiler” would be the one which fired slowest and ran tho propeller at the lowest velocity.F. G. Fowler. Bridgeport, Conn, Improvement In Farm Gates. Nothing iS more unsightly around a farmer's house than a dilapidated farm gate. Many improvements have been patented, but the one illustrated herewith is among the latest. As these modern gates have been adopted by farmers a vast impr0vement in the appearance of country homes is apparent. The gate shown in the annexed engraving is claimed to possess advantages not to be found in any °ther in use. Fig. 1 sh0ws this gate partially opened ; and Fig. 2 shows it entirely opened, and held from closing by a latch. In Fig. 1 if the gate should be slid to the left it would meet the pOst., A, and the latch, B, engaging with the p°st would fasten it shut. -When partially opened, the gate rests on a block, C, at the middle of the bottom, with a notch at the top to admit the bottom rail of the gate, the first motion in opening being a sliding to the right. It has a wooden hinge bar, D, composed of two pieces of timber playing on each side of the gate, with a gudgeon or hinge pin, E, at the top and a similar one at the bottom. This hinge bar stands at the angle shown in Fig. l, when the gate is closed and remains in that position unttU the middle vertical bar of the gate meets if as the gate is slid open. A roller, F, between the two parte of the hinge post, D, allows the gate to be alid back to the position show in Fig. 1 without disturbing the position Of D. A cord running from tlie post, G, to the top of D, limits the inclination of the latter In opening the gate after it has reached the position shown in Fig. 1, it engages with the hinge post, D, the boU°m of which is held by, and plays in a step H. Tim hino-e post is then thrown back to a vertical position, lifting and carrying the gate with it until the gudgeon E enters a slotted bearing, I, nailed on to the tops of the posts G and 1. These posts are not set one directly in front of the other, but one a little to one side of the other to allow the gate to swing between them. As soon as the hinge post, D, reaches the vertical positi°n the gate is balanced on its center of gravity ,and may be rotated upon D until it reaches the position shown in Fig. 2, in which it is held by the latch L. - Fig. 2 shows by the dotted lines the first position of the gate and also exhibits the positions of the different parts when the gate is fully opened. The hinge post, D, may be made of a proper length to elevate the gate above snow in winter, and the gate may be unhung as readily as gates with the common hinges. Nothing but wood and common nails are employed in its construction. Patented April 27, 1869, through the office ^ ; j- of the Scientific American,!^ ^.Mox^ whom address for further information at Owasso, Mich. See advertisement on another page. _iiam i IP Mti, i Suspension Bridge". In the construction of suspension bridges, the ties, or ropes from the main cable, sustaining the roadway, are of twisted wire as well as the; main cable. With the alleged advantages of twisted wire ropes, for this purpose, over straight iron rods, ! am not aware that the less expansion and contraction of the wire ^p^ “by changes of temperature, have been recognized. A hempen rope will contract in length when wetted, owrng to the minute particles of water acting as wedges, increasmg the width and the convexity of its spiral curves. The fibres of the same hemp laid straight, will not be shortened by wetting, but when in small fragments, as when made into paper, will be expanded in a similar manner by wetting. An iron rod and wire rope of equal lengths would expand equally by heat, waiving the above referred-to property, but the wires of the rope being in contact, and expanding laterally, would, by an equivalent wedge-like action, increase the convexity of the curves and tend to shorten the rope. By a reverse operation cold contracts and flattens the spiral curves, and tends to lengthen the wire rope,as with the hempen rope, when dried and stretched.—W. BakeweU. ing. This mud readily runs off on opening the sludge valve of the boiler. Increase of Weight During Combustion. The Chemical News gives a description of an interesting experiment. A small horseshoe magnet is hung up at the beam of a balance sufficiently sensitive to turn with centigrammes; the poles of the magnet are immersed for a moment in the ltmatura Jerri of the chemists' shops, and a beard of small particles of iron is caused to adhere to the poles ; by means of proper weights placed on the scale-pan at the other end of the beam the equilibrium is restored. This having cessed toallow the air to flow freely up around and to enter the interstices of the grate as well at the back as the front. By similar means the air also enters the ends of the grate to sut41y all parts of the incandescent coal equally with the oxygen necessary to combustion. The air also becomes heated in this chamber previous to entering the fuel, and is thus in the best condition to favor combustion. The ashes, when the grate is stirred, fall back into the recess instead of pouring forth into the apartment, and thus one of the objections to the use of grates, which has greatly retarded the employment of this most wholesome and pleasant of all the means employed for burning coal in dwellings is removed. The inventor caims that the use of this grate will cure smoky chimneys on account of the more perfect draft secured. The back is made separate, and can be used with ordinary baskets, in grate fronts of any pattern and with all grates by re-setting. It is simple in construction, and not liable to get out of order. The inventor also states that air-heating compartments are successfully used in connection with it. State and county rights may be obtained on application to the inventor, who will also furnish full-sized patterns gratis to purchasers. Patented through the Scientiflc American Patent Agency, August 25, 1868, by G. H. Mc- Elevy, Newcastle, Pa., who may be addressed for further information. MOXLEY'S FARM GATE. been done, the finely-divided iron is kindled, by approaching to it the flame of a Bunsen gas burner, and continues to burn. While burning, it will be seen that the arm of the balance on which the magnet is suspended considerably deviates from the horizontal position, thus indicating an increase of weight on the side where the experiment is going on. This experiment succeeds best with a magnet of moderate dimen sions ; the horseshoe magnet applied in this instance weighed, without its armature, 210 grammes, and can bear a load of 12'5 grammes of iron ; when this is altogether converted in magnetic oxide, by combustion, the increase in weight will be about 4*7 grammes.